Articles from Wikipedia or any other open source information may be imported and wikified. Articles which were published under the GNU Free Documentation License fall under that license and there should be a link back to the source placed at the bottom of the page. The URL of the "Permanent link" is best. In the case of articles which fall under another open source license such as Creative Commons the license and its general terms should be set forth at the foot of the body of the article, with a link to its full terms in addition to a link to the source.
Wikinfo has a problem with stale articles imported from Wikipedia. While this situation is acceptable, creation of new material or improvement of existing material is more desirable.wf:Wikinfo:Importing articles